I am trying to follow the tutorial on the Before We Start page of the data carpentry website, but after the instructions have me download a data set, it tells me to move it into the working directory, but I don't know how.
The output from running getwd() will be your working directory. Just move the file to that location.
Alternatively, copy the downloaded dataset into a folder of your choice, say carpentry, and then enter the full path in your read statement, such as
df <- read.csv("C:/Users/William/Desktop/carpentry/carpentry.csv")